Honing machine

ABSTRACT

A honing machine for machining workpieces that have at least one bore to be machined by means of honing, comprises a plurality of workstations (180-1, 180-2), wherein at least one of the workstations is configured as a honing station (180-1, 180-2) that comprises at least one honing unit (150-1, 150-2) that has a spindle shaft (152) that is rotatable about a vertical spindle axis (155) by means of a rotary drive and is movable back and forth parallel to the spindle axis by means of a reciprocating drive. The honing machine has a pallet transport system (200) internal to the machine, for transporting workpieces from and to the workstations (180-1, 180-2) by means of pallets (210-1, 210-2). The pallet transport system (200) is designed such that different transport paths are freely configurable via a control unit (190) of the honing machine (200).

FIELD OF APPLICATION AND PRIOR ART

The invention relates to a honing machine for machining workpieces that have at least one bore to be machined by means of honing.

Honing is a method for cutting using geometrically undefined cutters, in which a honing tool performs a cutting motion consisting of two components and a continuous surface contact is present between one or more cutting material elements, for example honing stones, of the honing tool and the inner surface of the bore to be machined. The kinematics of a honing tool are characterized by a superimposition of a rotational movement and a reciprocating movement which runs in the axial direction of the bore and which in most honing methods is an oscillating movement back and forth. In many applications, an expansion movement which leads to a change in the effective diameter of the honing tool is also provided.

The kinematics of the honing tool generates a surface structure with intersecting machining traces on the inner surface of the bore. Surfaces finished by honing are able to meet extremely high requirements regarding dimensional and shape tolerances and in some cases have a specific surface roughness and structure which combines a low degree of wear, due to a high material contact area, with the capacity to be able to obtain in a simple manner an oil film for the lubrication. Thus many highly stressed sliding surfaces in engines or engine components or inner surfaces of bores in hydraulic blocks or housings of injection pumps are machined by honing.

In many cases, a plurality of different successive honing operations are performed during the machining of the inner surfaces of bore, for example a pre-honing for generating the required basic shape and a final honing by which the ultimately required surface structure is generated. The success of the machining may be monitored by measuring steps.

The term “honing machine” denotes in this application a numerically controlled machine tool by which at least one honing operation may be performed on a workpiece, so that in this regard the machine tool is suitable for honing. The honing operation is performed at a honing station. A honing station is a workstation which has at least one honing unit. A honing unit of the type considered herein has a spindle shaft which is rotatable by means of a rotary drive about a vertical spindle axis and is movable back and forth by means of a reciprocating drive parallel to the spindle axis. The spindle shaft has on a tool-side end an apparatus for fastening a honing tool. The honing machine may be designed as a pure honing machine in which all of the workstations (machining stations) which are set up for the workpiece machining are designed as honing stations. Optionally other typical material-removing machining operations may be additionally performed by the honing machine on a workpiece, for example one or more drilling operations, a deburring operation and/or a brushing operation. To this end, corresponding workstations (machining stations) may be provided. At least one measuring station may also be optionally integrated therein.

Since a generic honing machine has a plurality of workstations which are arranged spatially separate from one another, a transport system internal to the machine is provided for transporting workpieces from and to the workstations. This transport system is configured as a pallet transport system in which the transport of workpieces from and to the workstations is performed by means of pallets. A machine concept of a generic honing machine is described in chapter 15.3 of the textbook: Flores, Gerhard, “Grundlagen and Anwendungen des Honens” (Principles and Applications of Honing), Essen: Vulkan Verlag, 1992. In order to carry out the honing of a V8 block in series production, a transfer honing machine has been designed with three honing stations, a measuring station and a circulating pallet transport. The cylinder bore is honed at the first two honing stations. The third honing station serves for machining the main bearing bore. The workpieces pass via suitable conveying apparatuses into the machining line of the machine from a loading and unloading station in which the blocks are mounted on carrier pallets. NC tables with built-on pivoting apparatuses which bring the respective bore of a block into the desired machining position by pivoting and moving in the X- and Y-directions, are located at the honing and measuring stations.

Object and Solution

It is an object of the invention to provide a generic honing machine which is characterized by a high degree of flexibility during use and a potential for high output.

To achieve this object, the invention provides a honing machine having the features of claim 1.

Advantageous developments are specified in the dependent claims. The wording of all of the claims is made with reference to the contents of the description.

The honing machine is provided for machining workpieces which have at least one bore to be machined by means of honing. The honing machine comprises a plurality of workstations, thus it may have for example two, three, or four workstations arranged spatially separated from one another. At least one operation on the workpiece is carried out at a workstation. Workstations at which the workpiece is changed in terms of its properties by, for example, material-removing machining, are also denoted as machining stations. A measuring station is an example of a workstation at which a machining which changes the workpiece is not performed.

At least one of the workstations is configured as a honing station. Within the context of the present application this means that the workstation comprises at least one honing unit that has a spindle shaft that is rotatable about a spindle axis by means of a rotary drive and is movable back and forth parallel to the spindle axis by means of a reciprocating drive. The spindle axis is oriented vertically.

The transport system internal to the machine for transporting workpieces from and to the workstations is designed as a pallet transport system which operates by means of pallets. The term “pallet” denotes here a changeable workpiece carrier on which a workpiece holding device or a plurality of workpiece holding devices are attached or are able to be mounted in order to hold a workpiece in a desired position on the pallet.

Optionally, a workpiece holding device may also comprise a rotary apparatus in order to rotate a received workpiece about at least one rotational axis in a targeted manner and thereby to be able to change the orientation thereof relative to the pallet.

According to one formulation of the invention, the pallet transport system is designed such that different transport paths are freely configurable via a control unit of the honing machine. “Freely configurable” means in this context that a transport path may be selected and used from a finite plurality of transport paths which are possible in terms of construction and control technology. “Freely” thus does not mean “in any manner”. Thus it is possible, amongst other things, to transport workpieces on different previously selectable transport paths from one loading position to one or more workstations, and to transport workpieces away from these again, in particular back to the same loading position. If a plurality of workstations are intended to be used, these workstations may be operated in a different sequence or even at the same time. The term “operate” means in this context that a pallet may be transported toward a workstation or transported away therefrom by means of the pallet transport system.

The coordination of the timing of the operation of workstations is thus selectable via the controller. It is also possible, starting from a loading position, to operate different workstations on different transport paths. If required, a loading and unloading may be carried out at different positions along transport paths. This is different from conventional circulating pallet transport systems in which a specific sequence of workstations to be successively approached during circulation is fixedly predetermined by the construction of the transport system. The variable usability of the workpiece transport provides a high degree of flexibility when using the honing machine. Moreover, there is a potential for high output, amongst other things, since optionally a plurality of operations may be performed at the same time independently of one another and in a phased manner. A loading and unloading parallel to the cycle time is also possible.

According to a development, the pallet transport system has four bi-directionally usable linear transport paths which are arranged in a rectangular arrangement, wherein transfer positions for the delivery of pallets between transport paths which are adjacent at right-angles to one another are arranged in corner regions of the rectangular arrangement. A rectilinear transport of a pallet in two opposing directions may selectively be used along a bi-directionally usable linear transport path. As a result, numerous combinations of transport paths and thereby many different transport paths which optionally may be made up to two or more linear transport paths may be configured. It is also possible to use only a single transport path in both directions for transporting to a workstation and for transporting away from the workstation.

The pallet transport system preferably has a plurality of (for example four) bi-directionally usable linear transport paths, wherein each of the transport paths has a single horizontally movable pallet carrier, transfer positions for the delivery of pallets between the adjacent transport paths are arranged between adjacent transport paths, and the pallet carriers of adjacent transport paths are configured in each case for a direct delivery of pallets without an additional transfer apparatus. In the transfer positions, therefore, no special aids have to be provided for the delivery or transfer of the pallets. The pallet carriers may thus be adapted to one another such that they may partially move into one another, wherein in each case one of the pallet carriers cooperating in the transfer position may perform reciprocating movements in order to be able to perform pallet lifting or lowering operations.

The honing machine may be constructed such that it provides different loading and unloading options. For example, a pallet may be loaded or unloaded at a transfer position. In an embodiment, the pallet transport system has a loading and unloading station (loading station) which is arranged on an operator side of the honing machine between the ends of a bi-directionally usable linear transport path. The loading and unloading station may be located, for example, centrally between the ends of the transport path which leads from one transfer position to a different transfer position on the operator side. This loading station may be used as a distributor station during loading, since the onward transport may be carried out in two different directions. Accordingly, pallets may also be transported to the loading station from two opposing directions. The flexibility of the honing machine when handling workpieces is thereby increased. A loading operation (for example, equipping a pallet held on a pallet carrier, removing a completely machined workpiece, installing or uninstalling an optionally already equipped pallet, or the like) may be performed as required manually, semi-automatically or fully automatically.

According to a development of the variant, with a rectangular arrangement of the transport paths at least one honing station is arranged in a corner region of the rectangular arrangement at a transfer position, such that pallets may be transported to and away from said honing station in two directions at right-angles to one another. Such a honing station may thus be loaded and unloaded from two directions located at an angle to one another. In this case, a pallet may be transported in one direction and transported away along the same transport path in the opposing direction. It is also possible to transport the pallet along a transport path and after use of the workstation to transport the pallet away in the other transport path located at an angle thereto.

In principle, it is possible that the honing machine has only one honing station. A significant contribution to increased flexibility and output is achieved in some embodiments by the honing machine having a first honing station and a second honing station which is usable independently therefrom, wherein the honing stations are arranged in transfer positions at opposing ends of a linear transport path. Thus a multi-spindle honing machining may be performed as required in a compact installation space, either at the same time at both honing stations and on different workpieces or at different times on the same workpiece or on different workpieces.

Preferably, exactly two honing stations are provided, said honing stations in each case preferably having only a single honing unit. As a result, a good compromise is able to be achieved between the complexity of the construction and the flexible usability.

In some embodiments, the honing unit of at least one honing station is arranged on a horizontal carriage which is horizontally movable parallel to a first direction. Thus a horizontal machine axis, which permits a monitored, accurately controllable movement and positioning of the honing unit in a horizontal direction by means of an NC drive, is provided. Thus the spindle axis may be moved to different positions relative to an optionally stationary workpiece, by moving this horizontal carriage in the first direction.

In an embodiment of the honing machine with a first honing station and a second honing station which is usable independently thereof, preferably the two honing units are arranged in each case on such a horizontal carriage and the horizontal carriages may be activated independently of one another. The horizontal carriages may run on the same guide rails, which simplifies the construction.

In some configurations, it may be sufficient if the horizontal carriage bears only one honing unit and otherwise no further machining unit or working unit. An additional flexibility regarding the type of different working operations may be achieved in some embodiments by the horizontal carriage bearing in addition to the honing unit at least one further working unit which accordingly may also be moved horizontally and positioned at different positions. A further working unit, for example, may be a deburring unit which may bear a deburring tool which may also be positioned by moving the horizontal carriage in the first direction. Alternatively or additionally, it is also possible that a further working unit is provided in the form of a measuring unit which, for example, has a measuring head which may be lowered into a bore. The horizontal carriage may also be used for the positioning of the measuring head in the first direction.

Some embodiments are characterized in that the pallet transport system has at least one pallet carrier which is horizontally movable both in at least one horizontal direction and is additionally movable in the vertical direction, i.e. parallel to the spindle axis of a honing unit, in each case vertically in two opposing directions, i.e. bi-directionally. If the horizontal transport path which is usable by the pallet carrier leads to a workstation and away therefrom, it may be achieved that the pallet transport system in the region of a workstation may function at the same time as a functional component of a workpiece positioning system (part positioning system) in order to position the bore to be machined exactly in a desired position relative to the spindle axis of a honing unit (or a different working unit working with an axis).

The controlled vertical movement may serve, for example, for bypassing component defects and/or for enabling components of different heights, having the same or a similar component geometry, to be machined in a uniform manner.

It is possible to design the construction such that the pallet carrier in each case is able to be moved bi-directionally in two horizontal directions perpendicular to one another and in the vertical direction. Thus all degrees of freedom of movement for positioning a pallet or a bore of a workpiece borne thereby could be implemented in a Cartesian coordinate system on the workpiece side.

In embodiments which have a horizontal carriage which is movable bi-directionally and parallel to the first direction on a workstation and which bears a honing unit and/or a further working unit, a single horizontal machine axis may suffice on the part of the pallet carrier in order to implement all degrees of freedom of positioning. As a result, a simplified construction is possible.

Some embodiments are characterized in that the pallet transport system has at least one pallet carrier which is movable horizontally and parallel to a second direction perpendicular to the first direction, and which is additionally movable parallel to a third direction parallel to the spindle axis, vertically in two opposing directions, i.e. bi-directionally. It may also be achieved thereby that the pallet transport system in the region of a workstation may function at the same time as a functional component of a workpiece positioning system (part positioning system) in order to position a bore to be machined exactly in a desired position relative to the spindle axis of a honing unit (or a further working unit operating with an axis). A positioning of the workpiece by workpiece movements parallel to the second direction and to the third direction is possible by means of a horizontally and vertically movable pallet carrier. A relative movement to a working unit in the first direction perpendicular to these two directions may be achieved by a corresponding movement of the horizontal carriage which bears a honing unit and/or a different working unit.

Preferably, such a horizontally and vertically movable pallet carrier is provided for each workstation, in particular for each honing station.

In order to achieve a high degree of positioning accuracy of the workpiece relative to the working unit (one or more) of a workstation, in some embodiments it is provided that the (horizontally and vertically movable) pallet carrier has components of a zero point clamping system on its upper face provided for receiving a pallet. For example, clamping bushes may be attached to the upper face, said clamping bushes being able to be actuated for example by means of hydraulics or pneumatics and cooperating with corresponding clamping pins on the lower face of the pallets. By means of the zero point clamping system, a relationship may be provided between the machine coordinate system and the pallet coordinate system and thus also with the workpiece coordinate system, so that a positioning of the workpiece relative to a working unit is possible in a reliable and accurately repeatable manner by means of the controller of the honing machine.

Preferably, the pallets have auxiliary positioning apparatuses for assisting the positioning of a pallet in a target position on the pallet carrier. For example, clamping pins which are used within the context of the zero point clamping system may be part of the auxiliary positioning apparatuses.

A pallet may be designed as a passive component without a sensor system or actuator system. In many cases, however, it is provided that pallets (active pallets) which have one or more controllable components and corresponding actuators (one or more) and sensors (one or more) are used. As a result, in the case of corresponding activation by the control unit of the honing machine, for example, it is possible to generate workpiece movements relative to the pallet by means of the controllable components of a workpiece holding device mounted on the pallet, for example, and to pass feedback to the control unit via signals from sensors regarding the set position and/or orientation. For example, a workpiece holding device may have a controllable rotary or pivoting apparatus for setting different rotary positions of the workpiece.

In order to be able to use the potential of active pallets, in some embodiments it is provided that the pallet transport system has at least one horizontally and vertically movable pallet carrier which has automatically couplable interface components for transmitting energy and/or signals between the honing machine and a pallet borne by the pallet carrier. For example, an automatically producible and releasable fluid connection may be provided to an actuator, for example a pneumatic actuator, of the pallet. For transmitting signals, corresponding electrical contact elements may be provided on the pallet carrier and pallet, and optionally also a transmission system operating in a contactless manner.

Thus one aspect of the invention may also be formulated such that a honing machine is provided with a pallet transport system in which the pallet transport system is a functional component of a workpiece positioning system which is integrated in the honing machine and which is configured to position a workpiece with a known position in the region of a workstation, both in at least one horizontal direction and vertical direction.

BRIEF DESCRIPTION OF THE DRAWINGS

Further advantages and aspects of the invention emerge from the claims and from the following description of preferred exemplary embodiments of the invention which are described hereinafter with reference to the figures.

FIG. 1 shows an oblique perspective view of components of a honing machine according to an embodiment from its operator side;

FIG. 2 shows a plan view of the honing machine of FIG. 1;

FIG. 3 shows a side view of a vertical section through the honing machine of FIG. 1 and FIG. 2.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

FIG. 1 shows an oblique perspective view of components of a honing machine 100 according to an embodiment from its operator side, which also serves as the loading and unloading side. FIG. 2 shows a plan view and FIG. 3 shows a side view of a vertical section of the honing machine. The cladding parts present in the honing machine, which is mounted so as to be ready for operation, are not shown.

The honing machine 100 is a computer numerically controlled machine tool, the controllable components thereof being controlled via a central control unit 190.

The honing machine has a rectangular machine base 110 which bears all of the mechanical components of the honing machine. The machine base has in a first direction of the honing machine—corresponding to the x-direction of the machine coordinate system MCS—a width which is greater than the length in the second direction which is perpendicular to the first direction and which corresponds to the y-direction of the machine coordinate system MCS. The first direction is also denoted here as the transverse direction and the second direction as the longitudinal direction. The dimensions in the longitudinal and transverse direction permit a transport of the completely preassembled machine base on conventional transport means, for example by means of a truck or rail vehicle.

Side walls 120-1, 120-2 are built on the machine base along both longitudinal sides, in each case on the edge. These side walls bear on the rear face of the machine base 110 a torsionally stiff cross member 122 which is a component of the rear wall. The side walls and the rear wall enclose the working chamber 115 of the honing machine which is accessible from the operator side.

Two horizontal guide rails 130 are fastened one above the other on the front side of the cross member 122 facing the working chamber, said guide rails extending substantially over the entire free front face of the cross member into the region of the rear corner regions of the working chamber.

Two horizontal carriages 135-1, 135-2 are arranged on the guide rails, said horizontal carriages in each case being movable and being accurately positionable horizontally and independently of one another parallel to the first direction (x-direction) by means of numerically controlled drives. In the configuration shown, each of the horizontal carriages bears on the front face of a carriage plate 136-1, 136-2 a honing unit (first honing unit 150-1 or second honing unit 150-2), an adjacently arranged deburring unit 160-1 or 160-2 and an adjacently arranged measuring unit 170-1 or 170-2. These working units are arranged axially parallel to the honing unit. Other configurations, for example without the measuring unit and/or without the deburring unit, are possible.

Each of the honing units 150-1, 150-2 has a spindle shaft 152 which is rotatable by means of a rotary drive about a vertical spindle axis 155 and which is movable back and forth by means of a reciprocating drive parallel to the spindle axis. Some details may be identified in FIG. 3. In the exemplary embodiment, a honing unit 150 comprises an elongated base member 151 which is able to be fixedly mounted on the horizontal carriage 135-2 and which may be fixedly mounted directly on the front face of the horizontal carriage 135-2. Moreover, a spindle unit 158 is provided, said spindle unit being borne by the base member and the spindle shaft 152 being rotatably mounted therein. The spindle shaft is rotatable by means of a rotary drive integrated in the spindle unit (also denoted as the spindle motor) about its vertical spindle axis 155 (rotational axis of the spindle shaft). The spindle shaft has an apparatus for fastening a honing tool (not shown) on a tool-side end. The honing tool may be fastened directly or indirectly by means of an articulated rod or a further interposed apparatus to the spindle shaft. A linear guidance system for guiding a linear vertical reciprocating movement of the spindle unit 158 relative to the base member 151 is arranged between the base carrier 151 and the spindle unit 158. In the example, the spindle unit is mounted on a carriage. A reciprocating drive is provided for generating the reciprocating movement of the spindle unit. In the example, the reciprocating drive has an electric linear motor with a primary part and a secondary part which are movable relative to one another parallel to the longitudinal direction of the longitudinal guidance system (substantially parallel to the spindle axis 155). In the example, the primary part operated by electrical current is attached to the carriage or the spindle unit 158, which is also operated by current, whilst a series of permanent magnets are arranged inside the base member 151. A reverse arrangement is also possible. In the example, an expanding drive for expanding the honing tool is also provided. The expanding drive may be coupled, for example, to a feed rod running in the interior of the spindle shaft. The expanding drive is located in the upper part of the housing which also contains the spindle motor.

Thus a workstation of the honing machine 100 is formed in each of the rear corner regions of the working chamber 115, namely a first workstation 180-1 at the rear left and a second workstation 180-2 at the rear right. Both workstations are configured as honing stations since honing operations may be performed on suitably positioned workpieces by means of the honing units 150-1, 150-2 which may be operated independently of one another. Since the horizontal carriages 135-1, 135-2 in each case also bear a measuring unit and a deburring unit, with corresponding activation the workstations may alternatively or additionally be used as a deburring station and/or as a measuring station.

The honing machine has a pallet transport system 200 internal to the machine which is designed for transporting workpieces from and to the workstations 180-1, 180-2 by means of pallets 210-1, 210-2. In this case, the term “pallet” denotes changeable workpiece carriers which in the example have a solid plate made of steel, on which further functional components (for example auxiliary positioning apparatuses, apparatuses for mounting workpiece holding devices) are attached. All of the mechanical components of the pallet transport system 200 are borne directly or indirectly by the machine base 110. The pallet transport system 200 is designed structurally and in terms of control technology such that different transport paths are freely configurable via the control unit of the honing machine.

In the exemplary embodiment, the pallet transport system 200 comprises exactly four linear or rectilinear transport paths 202-1 to 202-4 which in each case may be used bi-directionally, i.e. in two opposing directions. The transport paths run in each case horizontally and are arranged in a rectangular arrangement. In this case, a first transport path 202-1 runs on the left-hand side of the working chamber 115 between the operator side and the first workstation 180-1. A second transport path 202-2 runs on the opposing right-hand side of the working chamber 115 between the operator side and the second workstation 180-2. These two transport paths 202-1, 202-2 run in each case parallel to the second direction (y-direction or longitudinal direction) in the vicinity of the inner faces of the side walls facing one another. The two other transport paths, i.e. a third transport path 202-3 and a fourth transport path 202-4, run perpendicular thereto, i.e. in the first direction or transverse direction, wherein the third transport path 202-3 runs in the vicinity of the front face (operator side) and the fourth transport path 202-4 runs in the vicinity of the rear face approximately below the cross member 122 and connects the two workstations 180-1 and 180-2.

Transfer positions 204-1 to 204-4 are provided in the corner regions of the rectangular arrangement, in each case where adjacent transport paths intersect virtually at right-angles to one another, said transfer positions serving for the direct delivery of pallets between transport paths which are in each case adjacent at right-angles to one another. As is described in more detail below, a single horizontally movable pallet carrier 260-1 to 260-4 is present in each of the transport paths. Transfer positions 204-1 to 204-4 for the delivery of pallets between the adjacent transport paths are arranged between adjacent transport paths. The pallet carriers of adjacent transport paths are configured in each case for a direct delivery of pallets without an additional transfer apparatus, so that in the transfer positions no specific aids have to be provided for the delivery or transfer of the pallets.

At the first transfer position 204-1 which is located on the operator side in front of the first workstation 180-1, a pallet may be transferred or delivered directly from the third transport path 202-3 to the first transport path 202-1, or vice versa. The second transfer position is located in the region of the first workstation 180-1. Accordingly, at the second transfer position 204-2 a pallet may be transferred in both directions directly between the first transport path 202-1 and the fourth transport path 202-4. The same applies to the third and fourth transfer position on the opposing longitudinal side.

It may be identified that, as a result, each of the workstations, i.e. both the first workstation 180-1 and the second workstation 180-2, in each case is arranged in a corner region of the rectangular arrangement of the transport paths of the pallet transport system in the region of a transfer position, such that pallets may be transported to said workstations and transported away therefrom in two directions at right-angles to one another.

For example, the first workstation 180-1 arranged to the rear left may be “served” both by the first transport path 202-1 and by the fourth transport path 202-4. Thus, for example, a pallet with a workpiece located thereon may be conveyed from the first transfer position 204-1 parallel to the longitudinal direction to the first workstation 180-1 and then in the opposing direction transported back again to the first transfer position 204-1. The same might also be possible along the fourth transport path. It is also possible to transport a pallet with at least one workpiece located thereon along the first transport path 202-1 from the first transfer position 204-1 to the first workstation 180-1 and after the machining to transport said pallet back at right-angles thereto by means of the fourth transport path 202-4 in the direction of the second workstation 180-2.

Structurally these functionalities are implemented as follows in the exemplary embodiment. For implementing the first transport path 202-1, two horizontal guide rails 230-1 are fastened to the inner face of the first side wall 220-1, shown to the left with a vertical spacing above one another. A horizontal carriage 240-1 runs on these guide rails, said horizontal carriage being able to be displaced horizontally in any direction by means of a numerically controlled drive with a high degree of positional accuracy parallel to the second direction (longitudinal direction). The horizontal carriage 240-1 bears on its side facing the working chamber 115 two guide rails 250-1 which run vertically (in the z-direction) and which bear a vertically movable carriage 260-1, which may be moved by means of a suitable numerically controlled drive in the vertical direction, i.e. parallel to the spindle axis 155 of the honing unit, in a numerically controlled manner in both directions.

The carriage 260-1 functioning as a reciprocating carriage serves as pallet carrier of the first transport path 202-1 and thus is also denoted as the first pallet carrier 260-1.

In the configuration shown, the pallet 210-1, which during operation may bear at least one workpiece clamping device with at least one workpiece mounted thereon, is located on the first pallet carrier 260-1. A correspondingly built reciprocating carriage or a second pallet carrier 260-2 without a pallet located thereon is shown on the opposing longitudinal side.

It may be clearly identified on the second pallet carrier 260-2 that the pallet carrier has two support elements 261 which are parallel to one another and which are designed in the manner of angle brackets, an intermediate space 262 being present therebetween. Two components of a zero point clamping system 265 are located in each case on the horizontal upper faces of the support elements. The four components of the zero point clamping system 265 attached to the pallet carrier are attached in a rectangular, in particular in a square, arrangement on the upper face of the pallet carrier and permit a positioning which is subject to only small tolerances of a pallet borne thereby. The zero point clamping system has in the configuration shown the clamping bushes, which are shown and which are attached to the upper face of the pallet carrier, and which cooperate with clamping pins on the lower face of the pallets and which may be actuated by means of hydraulics or pneumatics. Thus positioning accuracies of less than a hundredth of a millimeter are possible with a high degree of repeat accuracy. The first pallet carrier 260-1 is of similar construction.

The position of a workpiece-bearing pallet on the first or the second pallet carrier may thus be exactly predetermined and it is known to the control unit of the honing machine when the workpiece bearing device is mounted on the pallet at the reference points provided therefor and this pallet is clamped in the zero point clamping system.

Together with the highly accurately operating NC drives for the horizontal movement and the vertical movement of the first (or second) pallet carrier, therefore, a highly accurately operating workpiece positioning system (part positioning system) is provided, said workpiece positioning system being able to position a workpiece with a known position in the region of a workstation both in the longitudinal direction (y-direction, second direction) and in the vertical z-direction. Together with the horizontal mobility of the horizontal carriage which is precisely controlled relative to the x-position and which bears one or more machining units (for example a honing unit) of the workstation, therefore, an accurate positioning of the workpiece relative to a tool used on a workstation is possible in all three spatial directions (x-, y- and z-direction).

Already with the components described above, the honing machine may be used for accurate machining of bores by honing and/or deburring. For example, the first pallet carrier 260-1 may be moved initially into the position shown in the vicinity of the operator side. Here a pallet 210-1 with a workpiece holding device located thereon (not shown) and a workpiece clamped therein is positioned on the pallet carrier. In this case, a single tool may be positioned thereon. It is also possible to position a plurality of workpieces at the same time. Then the first pallet carrier 260-1 is moved to the rear along the first transport path 202-1 to the first workstation 180-1. There the spindle axis 155 of the honing unit is positioned in a coaxial position relative to the bore axis of the first bore to be machined. The relative movement possibly required therefor in the x-direction (first direction) is implemented by a horizontal movement of the honing unit. Possible positioning movements in the second direction (y-direction) and in the vertical direction (z-direction) are implemented via corresponding displacement movements of the pallet carrier 260-1. If the bore is arranged at the correct height and oriented toward the spindle axis, the honing may be performed in a manner known per se. A corresponding or completely different workpiece machining could be performed independently therefrom at the second honing station which in principle is constructed in a similar manner and which is operated by the correspondingly horizontally and vertically movable second pallet carrier 260-1.

A physical transport link between the two workstations 180-1, 180-2 in the rear corner regions of the working chamber 115 of the honing machine 100 is achieved by means of the third and fourth transport paths 202-3 and 202-4. A pair of guide rails, which run in the x-direction (transverse direction) and which are mounted on the machine bed, forms part of the third transport path 202-3 in the vicinity of the operator side. The guide rails 271-3 bear a base carriage 272-3 which may be moved horizontally by means of a numerically controlled drive bi-directionally in the transverse direction (x-direction) into end regions of the guide rails. The base carriage bears a further horizontally movable carriage 273-3 which has a separate drive and serves as a pallet carrier for receiving a pallet. Since the pallet carrier forms part of the third transport path 202-3, it is also denoted as the third pallet carrier 260-3.

The third pallet carrier 260-3 requires no components of a zero point clamping system on its upper face since an accurate workpiece positioning is not required by this pallet carrier. The third pallet carrier 260-3 has a width parallel to the longitudinal direction (y-direction) which is dimensioned such that when displaced in the first direction (transverse direction) it fits between the two angular support elements 261 of the vertically movable pallet carriers 260-1, 260-2 attached to the longitudinal sides. As a result, a direct delivery of a pallet between the third pallet carrier 260-3, which is movable in the transverse direction, and the first pallet carrier 260-1, which is also movable in the vertical direction, or the opposing second pallet carrier 260-2 is possible. The base carriage 272-3 and the further carriage 273-3 borne thereby in each case have a separate drive. As a result, the carriage 273-3 may be moved in the manner of telescope across the region of the lower carriage (base carriage) 272-3 and into the delivery region 262.

For example in the situation shown, if the pallet 210-1 located on the first pallet carrier 260-1 is to be transferred to the third pallet carrier 260-3 which is movable in the transverse direction, the reciprocating carriage of the first pallet carrier 260-1 is initially moved upwardly sufficiently far that the pallet is located above the level of the third pallet carrier 260-3. Then this third pallet carrier is moved horizontally into the region below the lifted pallet 210-1, by moving the base carriage 272-3 and by a superimposed movement of the further carriage borne thereby. Then the reciprocating carriage of the first pallet carrier 260-1 is lowered until the pallet bears against the third pallet carrier 260-3 and the reciprocating carriage is lowered even further so that the pallet is fully released therefrom. Then a transverse transport may be carried out in the x-direction by means of the third pallet carrier 260-3.

A reverse transfer is also possible. For example, in some exemplary embodiments a loading and unloading position or a loading and unloading station 185 is provided at the position shown of the third pallet carrier 260-3, centrally between the longitudinal sides. At the start, a pallet located on the third pallet carrier 260-3, with a workpiece holding device with a workpiece, may be mounted thereon. For the delivery of this pallet to the first pallet carrier 260-1 this first pallet carrier is initially moved downwardly so that the pallet may be moved by means of the third pallet carrier horizontally to the first transfer position 204-1 at a position above the vertically movable reciprocating carriage of the first pallet carrier 260-1. Then the reciprocating carriage with the first pallet carrier 260-1 is moved upwardly and at the same time takes the pallet directly from the third pallet carrier 260-3 without interposed transfer apparatuses. In this take-up operation or lift-off operation, the corresponding components of the zero point clamping system on the pallet 210-1 and the first pallet carrier 260-1 also come into engagement with one another so that as a result the position of the workpiece to be machined is defined relative to the honing machine.

Subsequently, the third pallet carrier which is movable in the transverse direction is again moved into the central position shown (loading and unloading position). As soon as a horizontal displacement movement of the first pallet carrier 260-1 is possible thereby, this first pallet carrier may be moved in the direction of the first workstation 180-1 in order to position the workpiece there.

The pallet carriers cooperating at a transfer position are thus adapted to one another such that they may partially move into one another, wherein in each case one of the pallet carriers cooperating in the transfer position may perform reciprocating movements in order to be able to perform pallet lifting or lowering operations.

The fourth transport path 202-4 running in the vicinity of the rear face of the machine base 110 connects in a similar manner the transfer positions 204-2 and 204-3 which in each case are located in the region of the workstations. The fourth pallet carrier 260-4 which is movable horizontally in the x-direction has the same degrees of freedom of movement as the above-described third pallet carrier 260-3 which is why reference is made to the description there.

By means of the fourth transport path 202-4 it is possible, for example, to take a workpiece, which has been initially machined at the first workstation 180-1, from the first pallet carrier 260-1 positioned there and to transport it to the second workstation 180-2, where the pallet with the workpiece is then taken from the associated second pallet carrier 260-2 and positioned for the workpiece machining.

It should also be mentioned that the transport paths 202-1 and 202-2, which lead in the longitudinal direction (y-direction) to the workstations, are designed relative to the possible transport paths such that the pallet carriers 260-1, 260-2 may be moved under the working units of the workstation sufficiently to the rear (into the region of the controller 190) that the working units are freely accessible from the front, for example in order to be able to perform a tool change comfortably without being impaired by a pallet carrier.

Using these few examples it may be seen that the honing machine 100 is a honing machine which may be used in a highly flexible manner and which preferably requires just two honing units, i.e. may have a twin-spindle design. The honing machine is suitable for parallel machining of workpieces at two different honing stations. In this case, however, workpieces could be loaded and unloaded parallel to the cycle time.

Workpiece positioning systems operating in a positionally accurate manner are implemented at both workstations, said workpiece positioning systems making it possible to drive in three axial directions perpendicular to one another, toward flexible component positions. The horizontally movable horizontal carriages 135-1, 135-2 form part of these component positioning systems, said horizontal carriages bearing the honing units (and/or other machining units) and the first and second pallet carriers 260-1, 260-2, which are movable into the region of the workstation and which, on the one hand, may be moved positionally accurately in a horizontal second direction (y-direction) perpendicular to the movement direction of the machining unit and, on the other hand, vertically (i.e. parallel to the spindle axis of the honing unit).

The workstations may be provided in each case with a honing unit so that they are configured in each case as a honing station. Additionally, one or more further working units, such as for example a deburring unit and/or a measuring unit, may be attached to the same horizontal carriage (or to a horizontal carriage which is movable separately therefrom). Not every workstation has to be configured as a honing station.

The pallet transport system 200 internal to the machine provides an important contribution to the high degree of flexibility in possible machining scenarios, said system being designed in terms of construction such that different transport paths are freely configurable via a control unit of the honing machine. In this case, in the embodiment shown, a maximum of three pallets are in use, wherein for example two pallets may be positioned at the same time in the region of the workstation during the machining and a pallet may be positioned in a loading position for loading or unloading. The pallet transport system of the exemplary embodiment may be described such that it contains an integrated workpiece positioning system, the horizontally and vertically movable first and second pallet carriers on the first and the second transport path being part thereof. On the other hand, the configuration may also be described such that the component positioning systems in the honing machine undertake both the task of component positioning relative to the machining unit and also tasks as part of the pallet transport.

It is also part of the overall concept that components may also be directly loaded or unloaded onto the pallets located in the machine, and entire pallets may be changed at the loading station. This case is advantageous, for example, if high set-up costs were to be necessary for the clamping and unclamping of workpieces. Pallets may thus also be set up outside the honing machine and then loaded when fully equipped.

The honing machine is very flexible and, in one working process on a pallet, is able to pick up and machine both components or workpieces with a relatively high individual weight and also many individual, generally smaller, workpieces at the same time. The advantages, amongst others, are a high output and also the possibility of a variable assignment of the honing spindle for single-spindle or twin-spindle processes.

The honing machine shown may illustrate, for example, the following machining scenarios. Scenario 1: honing, measuring, deburring of a workpiece with a bore; scenario 2: honing, measuring, deburring of a workpiece with a plurality of bores; scenario 3: honing, measuring, deburring of a plurality of workpieces with a bore; scenario 4: honing, measuring, deburring a plurality of workpieces with a plurality of bores; scenario 5: two-fold single-spindle process, wherein it is possible to hone and load twice at the same time; scenario 6: twin-spindle process, wherein it is possible to hone and load twice at the same time. 

1. A honing machine for machining workpieces that have at least one bore to be machined by means of honing, comprising: a plurality of workstations, wherein at least one of the workstations is configured as a honing station that comprises at least one honing unit that has a spindle shaft that is rotatable about a vertical spindle axis by means of a rotary drive and is movable back and forth parallel to the spindle axis by means of a reciprocating drive; and a pallet transport system internal to the machine, for transporting workpieces from and to the workstations by means of pallets, wherein the pallet transport system is designed such that different transport paths are freely configurable via a control unit of the honing machine.
 2. The honing machine as claimed in claim 1, wherein the pallet transport system has four bi-directionally usable linear transport paths which are arranged in a rectangular arrangement, wherein transfer positions for the delivery of pallets between transport paths, which are adjacent at right-angles to one another, are arranged in corner regions of the rectangular arrangement.
 3. The honing machine as claimed in claim 1, wherein the pallet transport system has a plurality of bi-directionally usable linear transport paths, each of the transport paths has a horizontally movable pallet carrier, transfer positions for the delivery of pallets between the adjacent transport paths are arranged between adjacent transport paths, and the pallet carriers of adjacent transport paths are configured for a direct delivery of pallets without an additional transfer apparatus.
 4. The honing machine as claimed in claim 2, wherein the pallet transport system has a loading and unloading station which is arranged on an operator side of the honing machine between, in particular centrally between, the ends of a bi-directionally usable linear transport path.
 5. The honing machine as claimed in claim 2, wherein at least one honing station is arranged in a corner region of the rectangular arrangement at a transfer position, such that pallets may be transported to and away from said honing station in two directions at right-angles to one another.
 6. The honing machine as claimed in claim 2, wherein the honing machine has a first honing station and a second honing station which is usable independently therefrom, wherein the honing stations are arranged in transfer positions at opposing ends of a linear transport path.
 7. The honing machine as claimed in claim 1, wherein exactly two honing stations are provided, said honing stations in each case preferably having a single honing unit.
 8. The honing machine as claimed in claim 1, wherein on at least one of the honing stations, preferably on all of the honing stations, the honing unit is arranged on a horizontal carriage which is horizontally movable parallel to a first direction.
 9. The honing machine as claimed in claim 8, wherein the horizontal carriage bears in addition to a honing unit at least one further working unit, in particular a deburring unit and/or a measuring unit.
 10. The honing machine as claimed in claim 1, wherein the pallet transport system has at least one pallet carrier which is horizontally movable in at least one horizontal direction and is additionally movable in the vertical direction, vertically and bi-directionally, wherein a horizontal transport path which is usable by the pallet carrier leads to a workstation and away therefrom.
 11. The honing machine as claimed in claim 8, wherein the pallet transport system has at least one pallet carrier which is movable horizontally and parallel to a second direction perpendicular to the first direction, and is movable parallel to a third direction parallel to the spindle axis, vertically and bi-directionally.
 12. The honing machine as claimed in claim 10, wherein the pallet carrier has components of a zero point clamping system on an upper face provided for receiving a pallet.
 13. The honing machine as claimed in claim 10, wherein the pallet carrier has automatically couplable interface components for transmitting energy and/or signals between the honing machine and a pallet borne by the pallet carrier.
 14. The honing machine as claimed in claim 1, wherein the pallet transport system is a functional component of a workpiece positioning system which is integrated in the honing machine and which is configured to position a workpiece with a known position in the region of a workstation, both in at least one horizontal direction and vertical direction.
 15. The honing machine as claimed in claim 1, wherein pallets of the pallet transport system have one or more of the following features: auxiliary positioning apparatuses for assisting the positioning of a pallet in a target position on a pallet carrier, wherein the auxiliary positioning apparatuses preferably have clamping pins which are usable in a zero point clamping system; at least one controllable component with actuators and sensors such that an activation of the controllable component is possible by the control unit of the honing machine, wherein preferably workpiece movements may be generated relative to the pallet by means of a controllable component of a workpiece holding device mounted on the pallet, and a feedback to the control unit is possible via signals from sensors regarding the set position and/or orientation. 